87 lines
2.7 KiB
Groff
87 lines
2.7 KiB
Groff
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.\" $NetBSD: isnan.3,v 1.2 2004/03/04 23:49:31 wiz Exp $
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.\"
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.\" Copyright (c) 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" From: @(#)isinf.3 8.2 (Berkeley) 1/29/94
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.\" from: NetBSD: isinf.3,v 1.10 2003/08/07 16:42:52 agc Exp
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.\"
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.Dd March 5, 2004
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.Dt ISNAN 3
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.Os
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.Sh NAME
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.Nm isnan
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.Nd test for not-a-number
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In math.h
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.Ft int
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.Fn isnan "real-floating x"
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.Sh DESCRIPTION
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The
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.Fn isnan
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macro determines whether its argument
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.Fa x
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is not-a-number
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.Pq Dq NaN .
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An argument represented in a format wider than its semantic type is
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converted to its semantic type first.
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The determination is then based on the type of the argument.
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.Ss IEEE 754
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It is determined whether the value of
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.Fa x
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is a NaN.
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.Ss VAX
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NaNs are not supported.
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.Sh RETURN VALUES
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The
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.Fn isnan
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macro returns a non-zero value if the value of
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.Fa x
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is a NaN.
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Otherwise 0 is returned.
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.Sh SEE ALSO
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.Xr fpclassify 3 ,
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.Xr isfinite 3 ,
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.Xr isinf 3 ,
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.Xr isinff 3 ,
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.Xr isnanf 3 ,
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.Xr isnormal 3 ,
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.Xr math 3 ,
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.Xr signbit 3
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.Rs
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.%T "IEEE Standard for Binary Floating-Point Arithmetic"
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.%Q ANSI
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.%R Std 754-1985
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.Re
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.Sh STANDARDS
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The
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.Fn isnan
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macro conforms to
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.St -isoC-99 .
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